Channel scan removing some channels (Remove duplicates?)

[danielwlewis]

Problem: Except for 700, 721 and 780, channels 700-799 are missing after a channel scan that finds more than 400 channels. The 700's do appear both on SchedulesDirect and in the Channel Lineup shown by the HDHomeRun Prime SetUp utility. I suspect the 700's are being removed as "duplicates" since Comcast also makes the same cable stations (with the exception of 700, 721 and 780) available in the 1000's. (This is a Comcast "feature", having to do with grouping of similar content.) I was going to try unchecking the default channel scan option of "Remove Duplicates" in the MythTV backend setup, but that option does not appear in the scan options menu.

Question: If the problem is indeed that the channel scan is removing these channels as duplicates, then how can I tell it not to do that?

My Configuration:

• MythTV v31
• SchedulesDirect XMLTV/JSON
• Comcast Cable and OTA Listings for 95014 (Cupertino, CA)

Thanks!
Dan

[kmdewaal]

The "Remove Duplicates" option should be visible in the Channel Scan dialog, below the "Full search for old channels" and above the "Add Full Transport Stream Channels" options.
If you cannot find this option it could be that there is an issue with the theme you are using. Please try with "MythCenter-wide" as that is what the software has been tested with.
It can also be a good idea to upgrade to the latest v31 version.
For ATSC it is possible to reduce the scan range by specyfing the lowest and the highest channel. This can be repeated so for example, if you want channels 10 to 20 and 30 to 40 but not 20 to 30 you can do one scan from 10 to 20 and a second scan from 30 to 40.

[danielwlewis]

Thanks for the quick response! There's no menu item between the "Full search for old channels" and "Add Full Transport Stream Channels" options, and yes - I am using the "MythCenter-wide" theme that was the installation default.

I would try your suggestion of limiting the scan range, but the range isn't specified in terms of station numbers (like 700-799) - it's in terms of QAM 256 cable channels.

The software was installed yesterday, so the version is very recent:

From "mythbackend --version":
MythTV Version: v31.0
MythTV Branch: fixes/31
Network Protocol: 91
Library API: 31.20200101-1
QT Version: 5.12.5

Any other suggestions?
Dan

[kmdewaal]

I have the latest v31/fixes and that does have the "Remove duplicates" option. However, if the option is not present in the MythCenter-wide Channel Scan page then the option should also not be activated.
Just in case, try updating your mythtv version to the latest v31/fixes by using the mythbuntu ppa. This is described here:
viewtopic.php?f=36&t=4453&p=22115&hilit=ppa#p22115
See also the Mythbuntu Control Panel which is now an Ubuntu application to deal with MythTV system configuration:
viewtopic.php?f=29&t=4483&p=22163&hilit=mcp#p22163

You can capture the output of a mythtv-setup channel scan like this:
mythtv-setup -v channel,chanscan 2>&1 | tee ms-20210629-2050.log
and post the log file (possibly gzipped) here, or on pastebin or on gmail.
This will have information about all channels found, about which transports are removed as being duplicates, and which channels are kept.
This has likely enough information to decide on a follow-up action, e.g. exactly which QAM channels to scan to end up with the channels you want.

[danielwlewis]

You can capture the output of a mythtv-setup channel scan like this:
mythtv-setup -v channel,chanscan 2>&1 | tee ms-20210629-2050.log
and post the log file (possibly gzipped) here, or on pastebin or on gmail.
This will have information about all channels found, about which transports are removed as being duplicates, and which channels are kept.
This has likely enough information to decide on a follow-up action, e.g. exactly which QAM channels to scan to end up with the channels you want.

Thanks, but I must have done something wrong. I opened a terminal window and entered the command,

mythtv-setup -v channel,chanscan 2>&1 | tee ms-20210629-2050.log

It ran the backend setup program and put me at the main menu. I assumed that I then needed to navigate to the channel scan and start a scan, which I did. But when it finished, the file ms-20210629-2050.log had a size of 0 bytes.

What am I missing?
Dan

[kmdewaal]

With the command given you must be able to write a file in the current directory. This can be tested by making a small file with a text editor.
Output redirection does depend on the shell that is used, the command given does work for bash but not for e.g. tcsh.
You can also create a log file in the current directory with the following command:

Code: Select all

mythtv-setup -v channel,chanscan --logpath=.

This will create a log file with a name like mythtv-setup.20210630170430.395671.log in the current directory.

[danielwlewis]

With the command given you must be able to write a file in the current directory. This can be tested by making a small file with a text editor.
Output redirection does depend on the shell that is used, the command given does work for bash but not for e.g. tcsh.
You can also create a log file in the current directory with the following command:

Code: Select all

mythtv-setup -v channel,chanscan --logpath=.

This will create a log file with a name like mythtv-setup.20210630170430.395671.log in the current directory.

Thanks! That seems to work. I'm capturing the log file now and will upload it when it's done.

Dan

[danielwlewis]

Here's the log from the channel scan. Please let me know if you see anything that would explain why it's not finding channels in the 700-799 range other than the three exceptions noted earlier.

Oops! I got an error message trying to post the file saying that the board attachment quota had been reached.

Thanks!
Dan

[danielwlewis]

I am so confused! I've deleted a number of channels using MythTV Backend Setup, closed it, reopened it and verified that they have not "magically" reappeared. Also verified that they no longer appear in MythTV Front End. However, although it's been more than 10 minutes since making those changes, the deleted channels still appear in MythWeb. Just to be sure I had the latest version of MythWeb, I entered the command "sudo apt-get upgrade mythweb", but it said that I already had the latest version.

What am I missing?

Dan

[kmdewaal]

About the log file, if you are into Google you can put the log on your Google drive and share a link for everybody to access. Also wetransfer.com is very convenient. Or you can send the log file directly to me (klaas.de.waal at gmail dot com).

About MythWeb, I do not use that myself so I cannot help you there. Hope somebody else chimes in for this.